The present invention relates to quick connect fasteners for holding panels together and, more particularly, to ¼ turn fasteners which can be fastened and unfastened quickly and repeatedly.
As can be seen from Prior Art FIG. 1, fasteners 10 of the ¼ turn type have been known which include a grommet 12, a stud 14 and a receptacle 16. The fastener 10 holds together two panels 18 and 20, with adjacent sides of the panels in contact with one another, by extending through openings 22 and 24 foamed in the panels to receive the fastener. The grommet 12 has a cylindrical body 26 sized to extend through the opening 22 in one of the panels 18, usually an outer panel, and one end of the cylindrical body 26 has a radially outward extending flange 28 to engage the outer surface of the outer panel 18. The stud 14 has a shaft 30, a head 32, a cross pin 34 extending through the shaft at an end opposite to the head, a cup member 36 slidable along the shaft and a spring on the shaft between the head and cup member and received in the cup member. The stud 14 is received in the grommet 12, with the head 32 of the stud being adjacent to the flange 28 on the grommet and a radially outward extending flange 38 on the cup member 36 engaging a radially inward extending flange 40 at the end of the grommet 12 opposite to the radially outward extending flange 28. This arrangement keeps the head 32 of the stud 14 biased by the spring slightly outward from the radially outward extending flange 28 at the outer side of the outer panel 18. The cross pin 34 on the stud 14 prevents the assembly of the grommet 12 and the stud 14 from separating from the outer panel 18. Due to the presence of the cross pin 34 and the stiffness of the spring, a tool is required to move the cup member 36 adjacent to the head 32 by compressing the spring and thereby providing sufficient distance between the cross pin and the cup member that the stud can be inserted, at an angle, into the grommet. However, the geometry of this arrangement limits the axial length of the grommets 12 which can be used. Specifically, when the axial length of a grommet 12 reaches a certain magnitude, the stud 14 cannot be inserted into the grommet even when the cup member 36 is adjacent to the head 32.
The receptacle 16 of the fastener 10 has a generally cylindrical body 42 and a flange 44 projecting radially outward from one end of the body. The receptacle body 42 defines a central opening and has cam and locking surfaces 46 defined at an end opposite the radially outward extending receptacle flange 44. The receptacle flange 44 is placed against and secured to a side of the other panel 20, usually an inner panel, opposite to the side contacting the first panel 18, with the receptacle body 42 extending away from the side of the panel 20 to which the flange is attached. The panels 18 and 20 are brought together so that the stud 14 and the receptacle 16 are in alignment. The head 32 of the stud 14 is engaged by a turning tool, such as a screwdriver, pushed inwardly against the bias of the spring, and turned ¼ turn with the cross pin 34 of the 30 in engagement with the cam and locking surfaces 46 of the receptacle 16. This action locks the fastener 10 in place with the two panels 18 and 20 in secure engagement with one another.
A drawback of such a fastener is that, for a stud of any particular length, the total thickness of the two panels for which the fastener is effective must lie within a very limited range, typically a range of 0.030 inches. If the total thickness lies outside the range, a longer or shorter stud 14 must be used. If the total thickness lies outside the range by more than a full width of the range, a stud 14 two sizes longer than the first size must be used. Accordingly, for most work, a variety of stud sizes must be purchased and kept on hand.
The outer diameter of the cylindrical body of the grommet is sized to engage the surface defining the opening through the outer panel, so that lateral shifting of the outer panel with respect to the fastener is prevented. As the thickness of the outer panel increases, the length of grommet required increases. However, longer grommets have also required longer studs to enable the cross pin of the stud to pass through the longer grommets, at an angle.
U.S. Pat. No. 5,716,180 (the “'180 patent”), and U.S. Pat. No. 5,795,122 (the “'122 patent”), which are incorporated herein by reference, each disclose fasteners that are adjustable to accommodate varying thicknesses of panels or different lengths of studs. Both the '180 patent and '122 patent disclose a fastener that includes an insert or “insert member” that is moveable relative to a receptacle mounted to one of the two elements that are fastened together. The insert has diametrically opposed cam and locking surfaces for receiving the above referenced stud and cross-pin. In addition, the insert has external threads that are sized to engage internal threads for rotating the insert and moving it relative to the receptacle thereby adjusting the distance between the grommet and locking surfaces. This may be advantageous if thickness of the panels vary.
The fasteners in the '180 patent and '122 patent also include a locking mechanism that fixes the insert against movement relative to the receptacle. The '180 patent discloses a compressible spring roll pin inserted into a slot formed by a groove on the outer periphery of the insert that is aligned with a groove on in internal surface of the receptacle. A second embodiment disclosed in the '180 patent refers to using a resilient member such as a nylon strip that is disposed in the grooves of the insert and receptacle. As disclosed the resilient member may take the form of an elongated member inserted in a groove formed on the external surface and threads of the barrel or insert member; or, the resilient member may take the faun of a pellet inserted into a radial bore formed in the insert.
With respect to the '122 patent, there is disclosed a locking clip on an external surface of the receptacle. The locking clip is generally shaped like a “G” and made of a resilient material such as spring steel. The laterally disposed lip or locking member fits through a slot the receptacle and into a groove on the insert locking the insert against movement relative to the receptacle. While both fasteners provide advantages of an adjustable fastener, there are some disadvantages. One such disadvantage, at least with respect to the compression spring and locking pin, is that in order to access the locking mechanism for these fasteners one of the panels must be removed. In some cases, several or multiple fasteners may be in place and must be disengaged in order to remove the panel, which can be time consuming. Accordingly, a need exists for an adjustable fastener that has a locking mechanism that can be accessed without the need of removing panels during installation of the same.